Researchers have shown that the use of nano-sized materials in combination with an “electronic wiring layer” can improve battery performance by delivering long-term cycle life and high rate capability. Various morphological features of nano-sized transition metal oxides involving nanoparticles, nanorods, nanowires and nanotubes have been fabricated via a wide spectrum of synthetic methods, such as sol-gel, hydrothermal, coprecipitation, polymerized complex, electrospinning and colloidal crystal template processes.

Core-shell combination

In recent work, scientists at Ajou University, Korea, have successfully demonstrated the formation of monodispersed core/shell ferrite/C nanoparticles by a simple two-step solution chemical route: low-temperature thermolysis of metal oleates and pyrolysis of a carbon source for application as high-capacity LIB electrodes. These prepared Fe3O4/C and CoFe2O4/C nanoparticles consist of both a high-capacity active core (ferrites) and an electroconductive shell (thin amorphous carbon) to bypass the drawbacks suffered through the facile aggregation of lithium-active nanoparticle electrodes.

Enhanced electron transport

The CoFe2O4/C nanocomposite electrodes show a high specific capacity that can exceed 700 mAh/g even after 200 cycles, along with enhanced cycling stability thanks to the favourable utilization of the high surface area by the ferrite nanoparticles and the efficient electron transport path through the surface conductive carbon from each active ferrite nanoparticles to a current collector.

Back in the lab, the team plans to explore the design of hybrid nanostructured anodes further by combining these nanoparticles with conductive nanowires or multi-walled carbon nanotubes.

More information can be found in the journal Nanotechnology.